I gather you still haven’t read the original post. Give it a try, and think on it.
If your most powerful team is a bunch of misfit heroes that don’t work well together then using them puts you at a disadvantage. You also need to consider well the order in which you use them. Don’t use your defense down hero after using your sniper. Don’t use your debuffer hero after attacking an opponent with riposte. And so on. And having multiple defense down heroes just negates one of them as they conflict. My strongest team is around 4650 but my typical raiding team is around 4200-4400 (depending on colour and opponent).
Mono is great if you get the boards but statistically that is only happening 20% of the time. There are four other colours that get in the way. And it is harder to rework the board when you are after just one colour.
Defense team is a different animal. For me, it is there just to ensure I stay in diamond. I don’t care if I lose there, it actually makes it easier to win when I attack if my cups are lower. Plus anytime I get up around 2800 cups I usually wake up in platinum